
The Newsletter of Lean Manufacturing Strategy
February
14,
2003
www.strategosinc.com
Rational
Lot Sizing
Small
lot production is an important element of Lean
Manufacturing. It smoothes production, eases scheduling, improves
quality in many ways and makes Kanban feasible. The problem is: What
does “small” really mean?
Some
experts insist that “small” means one piece. Others
assert that lot size is irrelevant. Still others waffle or avoid the
question by insisting that setup reduction cures everything. Of course,
setup reduction is a good thing (as Martha Stewart would say) but it
does not happen instantly. Toyota took many years to achieve SMED. So,
what do you do about lot sizing in the meantime?
Most
manufacturers take an intuitive approach to lot sizing which frequently
misleads. As a result, lot sizes are often much too large and some are
much too small.
Economic
Lot Sizing (ELS) has been widely discredited. But, used
properly, ELS is one of several valid considerations for a rational
decision. You can learn more about lot sizing on our website at:
www.strategosinc.com/lean_lot_sizing.htm
This
and subsequent pages discuss:
-
How
to make rational lot size decisions
-
Why
lot sizing is different for bottlenecks and non-bottlenecks
-
How
Setup Reduction impacts the lot size decision
-
How benchmarks make the
job easy
In
some respects, these ideas go against widely held beliefs among Lean
Manufacturing advocates and I expect disagreement. That's OK. Discussion
and debate is constructive and there are probably some things we’ve
missed.
All
The Best-
Q.
Quarterman
Lee
Strategos,
Inc.
3916
Wyandotte
Kansas
City MO 64111
816-931-1414
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